Field of the Invention
The present invention relates to a manufacturing apparatus for multi-fiber optical ferrule used in optical communication and, in particular, to a manufacturing apparatus suitable for manufacturing a multi-fiber optical ferrule having optical fiber holes in two or more rows.
Multi-fiber optical ferrules for accommodating a large number of fibers are of a plurality of types, including a single-row type in which fiber holes are formed in a row, and a multi-row type in which fiber holes are formed in two or more rows. FIG. 4 shows a multi-fiber optical ferrule in which fiber holes J are formed in two rows, and a guide hole K is formed on either outer side of the rows of fiber holes J.
As shown in FIGS. 6A and 6B, when manufacturing a two-row-type multi-fiber optical ferrule as shown in FIG. 4, an upper mold C and a lower mold D are conventionally prepared, each having V-grooves A for fiber holes and V-grooves B for guide holes. Pins for forming fiber holes E are placed in the V-grooves A for fiber holes, and pins for forming guide holes F are placed in the V-grooves B for guide holes. A rectangular spacer G is placed between the pins for forming fiber holes E, F and, in this condition, closing (butting) is effected with two or more molds, and resin is poured into a cavity formed by the molds to thereby manufacture a multi-fiber optical ferrule. However, there can be involved a variation in machining accuracy regarding the positions, configuration, depth, etc. of the V-grooves A for fiber holes and the V-grooves B for guide holes in the molds C and D. In particular, there can be a variation in the positions of the V-grooves A for fiber holes in the direction of the arrangement thereof. Thus, the multi-fiber optical ferrule formed by the molds C and D has a problem of the accuracy of the fiber holes J and the guide holes K (FIG. 4). To solve this problem, there has been conventionally proposed a method according to which the hardness of the material of the spacer G is lower than the hardness of the material of the pins for forming fiber holes E.
In the conventional technique, the hardness of the material of the spacer is lower than the hardness of the material of the pins for forming fiber holes E, so that the spacer G is likely to undergo deformation as shown in FIG. 7 as a result of the pins for forming fiber holes E being pressed against the spacer G every time closing is effected for molding. This deformation is aggravated as the molding is repeated, with the result that the positions of the fiber holes J and the guide holes K (FIG. 4) are subject to deviation.
A manufacturing apparatus for multi-fiber optical ferrule according to the present invention is of the type which includes two or more molds having fitting groove for an optical fiber in which pins for forming fiber holes can be placed and fitting groove for guide holes in which pins for forming guide holes can be placed, the pins for forming fiber holes being placed in the fitting groove for an optical fiber, the pins for forming guide holes being placed in the fitting groove for guide holes, a spacer in the form of a rectangular parallelepiped being placed between the pins for forming fiber holes, closing being effected with the two or more molds, and resin is poured into a cavity formed inside the molds to thereby manufacture a multi-fiber optical ferrule having two or more rows of optical fiber holes, in which the hardness of the spacer is equivalent to or higher than the hardness of the pins for forming fiber holes. Corner portions with respect to the arrangement direction of the pins for forming fiber holes of the spacer are formed as rectilinear inclined surfaces or rounded surfaces.